This invention relates to load-break fuse equipment comprising a tubular receptacle and, removably mounted within the receptacle, a load-break drawout assembly that comprises a fuse and the movable contact of a load-break switch.
Examples of load-break fuse equipment of this type are disclosed in U.S. Pat. Nos. 3,471,816--Giegerich; 3,628,092--Keto; and 4,059,816--Bonecutter et al. In certain applications of such load-break fuse equipment, the largest diameter single fuse that is receivable within the receptacle may not have sufficient current-carrying or current-interrupting capacity for the power circuit in which the equipment is to be connected. For such high current applications, it is conventional to provide two identical load-break fuse equipments of this type and to connect them electrically in parallel.
While this approach can provided increased current-carrying and current-interrupting capacity while the two load-break drawout assemblies are in place within their receptacles, it is subject to the distinct disadvantage that the desired current-interrupting capacity is not present during certain intervals while the load-break drawout assemblies are being removed from or being inserted into their receptacles. More specifically, if one of the load-break drawout assemblies of such prior equipment is withdrawn, the fuse of the remaining assembly must alone provide current interrupting ability until the remaining assembly is withdrawn. This same condition is, of course, present if one of the load-break drawout assemblies is inserted before the other one.